1. Field of the Invention
The invention relates to a high voltage direct current transmission system comprising a rectifier station and an inverter station connected by a DC line, which rectifier station includes uncontrolled valves and means for controlling the alternating voltage connected to the valves.
2. The Prior Art
In direct current transmissions where the rectifier side is constructed with uncontrolled valves, the direct current is controlled by the inverter station during normal operation, and therefore the transmission must be secured against overcurrents if the inverter voltage breaks down or in the case of a short-circuit on the line.